summaryrefslogtreecommitdiff
path: root/arch/arc
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-02-16 14:56:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-16 14:56:52 -0800
commita68fb48380bb993306dd62a58cbd946b4348222a (patch)
tree610722b25e4785c0232b23ba9d04c7b49efd89d3 /arch/arc
parentea44a160e6dc5d3d7c680ea72dfbabef80343839 (diff)
parent06f34e1c28f3608b0ce5b310e41102d3fe7b65a1 (diff)
downloadkernel-a68fb48380bb993306dd62a58cbd946b4348222a.tar.gz
Merge tag 'arc-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC updates from Vineet Gupta: "Some fixes, nothing too exciting this time as well..." * tag 'arc-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARC: fix page address calculation if PAGE_OFFSET != LINUX_LINK_BASE ARC: Fix earlycon build breakage ARC: Dynamically determine BASE_BAUD from DeviceTree arc: Remove unused prepare_to_copy() ARC: use ACCESS_ONCE in cmpxchg loop ARC: add some more comments to ret_from_fork ARC: fix /proc/cpuinfo for offline cpus
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/include/asm/pgtable.h3
-rw-r--r--arch/arc/include/asm/processor.h3
-rw-r--r--arch/arc/include/asm/serial.h23
-rw-r--r--arch/arc/kernel/devtree.c24
-rw-r--r--arch/arc/kernel/entry.S14
-rw-r--r--arch/arc/kernel/setup.c7
-rw-r--r--arch/arc/kernel/smp.c2
7 files changed, 47 insertions, 29 deletions
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index ffed3b2cf313..9615fe1701c6 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -257,7 +257,8 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
#define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0)
#define pte_page(x) (mem_map + \
- (unsigned long)(((pte_val(x) - PAGE_OFFSET) >> PAGE_SHIFT)))
+ (unsigned long)(((pte_val(x) - CONFIG_LINUX_LINK_BASE) >> \
+ PAGE_SHIFT)))
#define mk_pte(page, pgprot) \
({ \
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 210fe97464c3..4e547296831d 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -56,9 +56,6 @@ unsigned long thread_saved_pc(struct task_struct *t);
/* Free all resources held by a thread */
#define release_thread(thread) do { } while (0)
-/* Prepare to copy thread state - unlazy all lazy status */
-#define prepare_to_copy(tsk) do { } while (0)
-
/*
* A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
* get optimised away by gcc
diff --git a/arch/arc/include/asm/serial.h b/arch/arc/include/asm/serial.h
index 602b0970a764..744a6ae15754 100644
--- a/arch/arc/include/asm/serial.h
+++ b/arch/arc/include/asm/serial.h
@@ -10,26 +10,13 @@
#define _ASM_ARC_SERIAL_H
/*
- * early-8250 requires BASE_BAUD to be defined and includes this header.
- * We put in a typical value:
- * (core clk / 16) - i.e. UART samples 16 times per sec.
- * Athough in multi-platform-image this might not work, specially if the
- * clk driving the UART is different.
- * We can't use DeviceTree as this is typically for early serial.
+ * early 8250 (now earlycon) requires BASE_BAUD to be defined in this header.
+ * However to still determine it dynamically (for multi-platform images)
+ * we do this in a helper by parsing the FDT early
*/
-#include <asm/clk.h>
+extern unsigned int __init arc_early_base_baud(void);
-#define BASE_BAUD (arc_get_core_freq() / 16)
-
-/*
- * This is definitely going to break early 8250 consoles on multi-platform
- * images but hey, it won't add any code complexity for a debug feature of
- * one broken driver.
- */
-#ifdef CONFIG_ARC_PLAT_TB10X
-#undef BASE_BAUD
-#define BASE_BAUD (arc_get_core_freq() / 16 / 3)
-#endif
+#define BASE_BAUD arc_early_base_baud()
#endif /* _ASM_ARC_SERIAL_H */
diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c
index fffdb5e41b20..e32b54abff51 100644
--- a/arch/arc/kernel/devtree.c
+++ b/arch/arc/kernel/devtree.c
@@ -17,6 +17,28 @@
#include <asm/clk.h>
#include <asm/mach_desc.h>
+#ifdef CONFIG_SERIAL_EARLYCON
+
+static unsigned int __initdata arc_base_baud;
+
+unsigned int __init arc_early_base_baud(void)
+{
+ return arc_base_baud/16;
+}
+
+static void __init arc_set_early_base_baud(unsigned long dt_root)
+{
+ unsigned int core_clk = arc_get_core_freq();
+
+ if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
+ arc_base_baud = core_clk/3;
+ else
+ arc_base_baud = core_clk;
+}
+#else
+#define arc_set_early_base_baud(dt_root)
+#endif
+
static const void * __init arch_get_next_mach(const char *const **match)
{
static const struct machine_desc *mdesc = __arch_info_begin;
@@ -56,5 +78,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt)
if (clk)
arc_set_core_freq(of_read_ulong(clk, len/4));
+ arc_set_early_base_baud(dt_root);
+
return mdesc;
}
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 83a046a7cd06..d868289c5a26 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -736,16 +736,20 @@ ENTRY(ret_from_fork)
; put last task in scheduler queue
bl @schedule_tail
- ; If kernel thread, jump to its entry-point
ld r9, [sp, PT_status32]
brne r9, 0, 1f
- jl.d [r14]
- mov r0, r13 ; arg to payload
+ jl.d [r14] ; kernel thread entry point
+ mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
1:
- ; special case of kernel_thread entry point returning back due to
- ; kernel_execve() - pretend return from syscall to ret to userland
+ ; Return to user space
+ ; 1. Any forked task (Reach here via BRne above)
+ ; 2. First ever init task (Reach here via return from JL above)
+ ; This is the historic "kernel_execve" use-case, to return to init
+ ; user mode, in a round about way since that is always done from
+ ; a kernel thread which is executed via JL above but always returns
+ ; out whenever kernel_execve (now inline do_fork()) is involved
b ret_from_exception
END(ret_from_fork)
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 252bf603db9c..900f68a70088 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -412,6 +412,11 @@ static int show_cpuinfo(struct seq_file *m, void *v)
char *str;
int cpu_id = ptr_to_cpu(v);
+ if (!cpu_online(cpu_id)) {
+ seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
+ goto done;
+ }
+
str = (char *)__get_free_page(GFP_TEMPORARY);
if (!str)
goto done;
@@ -429,7 +434,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
free_page((unsigned long)str);
done:
- seq_printf(m, "\n\n");
+ seq_printf(m, "\n");
return 0;
}
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 20ebb602ea2f..6a400b1b0b62 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -221,7 +221,7 @@ static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
* and read back old value
*/
do {
- new = old = *ipi_data_ptr;
+ new = old = ACCESS_ONCE(*ipi_data_ptr);
new |= 1U << msg;
} while (cmpxchg(ipi_data_ptr, old, new) != old);